U.S. patent number 6,615,108 [Application Number 09/700,211] was granted by the patent office on 2003-09-02 for area coverage with an autonomous robot.
This patent grant is currently assigned to F. Robotics Acquisitions Ltd.. Invention is credited to Shai Abramson, Ronen Friedman, Ilan Peleg, Ehud Peless.
United States Patent |
6,615,108 |
Peless , et al. |
September 2, 2003 |
Area coverage with an autonomous robot
Abstract
There is therefore provided, in accordance with a preferred
embodiment of the present invention, a robotic system for
systematically moving about an area to be covered. The system
includes at least one boundary marker (48) located along the outer
edge of the area to be covered, a robot (40) with a navigation
system (41) and a sensor unit (43). The navigation system (41)
navigates the robot (40) in generally straight, parallel lines from
an initial location and turns the robot (40) when the robot (40)
encounters one of the boundary markers (48), thereby to
systematically move about the area to be covered. The sensor unit
(43) senses proximity to one of the at least one boundary marker
(48).
Inventors: |
Peless; Ehud (Even Yehuda,
IL), Abramson; Shai (Pardessia, IL),
Friedman; Ronen (Hod Hasharon, IL), Peleg; Ilan
(Tsur Yigal, IL) |
Assignee: |
F. Robotics Acquisitions Ltd.
(Kadima, IL)
|
Family
ID: |
11071478 |
Appl.
No.: |
09/700,211 |
Filed: |
April 13, 2001 |
PCT
Filed: |
May 11, 1999 |
PCT No.: |
PCT/IL99/00248 |
PCT
Pub. No.: |
WO99/59042 |
PCT
Pub. Date: |
November 18, 1999 |
Foreign Application Priority Data
Current U.S.
Class: |
700/245; 180/167;
180/168; 180/169; 180/211; 318/568.12; 318/580; 318/581; 318/587;
700/253; 700/254; 700/255; 700/258; 700/262; 700/302; 701/1;
701/50 |
Current CPC
Class: |
G05D
1/0219 (20130101); G05D 1/0261 (20130101); G05D
1/0265 (20130101); G05D 1/027 (20130101); G05D
1/0274 (20130101); A01D 34/008 (20130101); G05D
1/0227 (20130101); G05D 1/0236 (20130101); G05D
1/0272 (20130101); G05D 2201/0208 (20130101) |
Current International
Class: |
G05D
1/02 (20060101); G06F 019/00 () |
Field of
Search: |
;700/245,253,254,255,258,262,302 ;701/23,25,1,213,50
;318/568.12,580,587,581 ;180/211,160,167,169 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
0 774 702 |
|
May 1997 |
|
EP |
|
408255018 |
|
Oct 1996 |
|
JP |
|
409128045 |
|
May 1997 |
|
JP |
|
WO 96/38770 |
|
Dec 1996 |
|
WO |
|
Other References
Robotic & Automation at Lulea University, Robots at the
robotics deparmetn, no date, Internet, pp. 1-2.* .
Hicks et al., A survey of robot lawn mowers, 2000, Internet, pp.
1-8.* .
Irigoyen et al., RoboMow evaluation, 2000, Internet, pp. 1-9.*
.
Chandler et al., The next generation autonomous lawn mower, 2000,
Internet, p. 1.* .
Chandler et al., LawnShark: A new platform for autonomous mowing
and navigation, 1999, Internet. pp. 1-5.* .
Schelxig, Robomow, Mow, Mow your loan, Friday, Sep. 22, 2000,
Internet/Washington Post, pp. 1-3.* .
Redazione Internet Magazine, Self operating lawn mower, 2000,
Internet, p. 1, (itportal.it/tech/misc/selfoperating).* .
LawnNibbler, th automatic lawn mowing system, 1999, Internet, pp.
1-2, (lawnnibbler.com).* .
George's Mower Service, Fully automatic lawn mower from george's
mower service in Riverniew Florida, no date, Internet, pp. 1-2.*
.
Ehud Peless et al., Navigation Method and System for Lawn Mowers
and Other Autonomous Machines, U.S. patent application Ser. No.
08/554,691, filed Nov. 7, 1995..
|
Primary Examiner: Cuchlinski, Jr.; William A
Assistant Examiner: Marc; McDieunel
Attorney, Agent or Firm: Polsinelli Shalton & Welte
Claims
What is claimed is:
1. A robotic system for systematically moving about an area to be
covered, the system comprising: at least one boundary marker
located along an outer edge of the area to be covered; a robot for
systematically moving about said area to be covered, said robot
including a navigation system for navigating said robot in
substantially straight lines, substantially parallel to each other,
originally from an initial location and for turning said robot when
said robot encounters said at least one boundary marker; and a
sensor unit for sensing proximity to said at least one boundary
marker.
2. The system of claim 1, wherein said sensor unit includes means
for indicating proximity to an obstacle within said area to be
covered and said navigation system includes means for turning said
robot when said means for indicating indicate proximity to an
obstacle.
3. The system of claim 2, wherein said means for indicating is
selected from the group comprising: a contact sensor or a proximity
sensor.
4. The system of claim 2, wherein said navigation system includes
means for counting the number of laps needed to cover the area
between an obstacle and said at least one boundary marker.
5. The system of claim 2, additionally comprising: at least one
obstacle marker located along the outer edge of an obstacle.
6. The system of claim 5, wherein said at least one boundary marker
is an electrified wire receiving a first signal and said at least
one obstacle marker is an electrified wire receiving a second
signal.
7. The system of claim 5, wherein said at least one boundary marker
is a post having a first bar code and said at least one obstacle
marker is post having a second bar code.
8. A robotic system for systematically moving about an area to be
covered, the system comprising: at least one boundary marker
located along an outer edge of said area to be covered; at least
one obstacle marker located along the outer edge of an obstacle
within said area to be covered; a robot for moving about said area
to be covered; and a sensor unit for sensing proximity to said at
least one boundary marker and said at least one obstacle marker and
for differentiating between said at least one boundary marker and
said at least one obstacle marker.
9. A method of systematically moving a robot about an area
comprising at least one boundary marker located along at least a
portion of an edge of an area to be covered, the method comprising:
navigating said robot in a first substantially straight line from
an initial location; sensing proximity of said robot to said at
least one boundary marker; turning said robot when said robot
encounters said boundary marker; and navigating said robot in a
second substantially straight line, said second substantially
straight line being substantially parallel to said first
substantially straight line.
10. A method of systematically moving a robot about an area
comprising at least one boundary marker located along an outer edge
of the area and at least one obstacle marker located along an edge
of an obstacle within said area, the method comprising: providing
said robot to said area to be covered; sensing the proximity to at
least one of said at least one boundary marker or said at least one
obstacle marker; and determining whether said at least one of said
at least one boundary marker or said at least one obstacle marker
is a boundary marker or an obstacle marker.
Description
FIELD OF THE INVENTION
The present invention relates to autonomous robots generally and to
autonomous robots which move through an area in particular.
BACKGROUND OF THE INVENTION
Autonomous robots are known in the art and have been implemented as
household appliances, such as a lawnmower or a vacuum cleaner.
These household appliances operate by moving about an area to be
processed such that the entire area is covered by the end of the
operation.
Reference is now made to FIGS. 1A and 1B, which illustrate the
operation of one exemplary autonomous robot, described in U.S
patent application (Ser. No.) 08/554,691, filed Nov. 7, 1995, now
U.S. Pat. No. 6,255,793, and assigned to the common assignees of
the present invention. U.S. patent application (Ser. No.)
08/554,691 is incorporated herein by reference. FIG. 1A illustrates
the area in which the robot 10 operates and FIG. 1B illustrates the
elements, in block diagram form, of robot 10.
The autonomous robot 10 operates within an area marked with
boundary markers 12A. If there are fixed obstacles 14 in the area,
such as flower beds, trees, columns, walls, etc., these obstacles
are rimmed with further boundary markers 12B. The boundary markers
12 can be of any suitable type, such as an electrified wire, bar
coded posts, a radioactive posts, etc. The term "marker" will be
used herein for both posts and wires.
As shown in FIG. 1B, the robot 10 includes a navigation system 20
which receives data from an edge sensor 22 which senses when the
robot 10 approaches a boundary marker 12 where, if the marker is a
continuous wire, the term "marker" indicates the section of the
wire near the current location of the robot. The navigation system
20 also receives data from an odometer 24 which measures the
distance the robot 10 has moved and a compass 26 which measures the
current location of the robot 10.
Initially, the robot 10 is placed within the area to be covered.
The robot 10 moves toward the boundary (if it did not begin near
it) and then, as indicated by arrows 32, moves along the boundary,
following the boundary markers 12. During this process, the robot
10 uses the location information from the compass to produce a map
28 (FIG. 1B) of the area to be covered.
Once the map is complete, the robot 10 moves about the area to be
covered. Whenever it approaches a boundary marker 12, as sensed by
the edge sensor 22, the robot 10 changes direction and continues
until it reaches another boundary marker 12. If the boundary marker
12 appeared close to, but not at, its expected position, navigation
system 20 updates the map 28 to match the new information.
If the boundary marker 12 is sensed substantially within the area,
as determined by a comparison of the output of the compass 26 and
the information in the map 28, the boundary marker 12 must be one
which surrounds the obstacle 14. The robot 10 changes direction and
continues until it reaches another boundary marker 12. The robot 10
moves about the area to be covered until it has determined that all
sections of the map 28 have been covered.
However, it will be appreciated that creating the map 28 of the
shape of the area to be covered is time consuming. Due to the
inaccuracies of the compass 26 and odometer 24, it is also
typically error prone.
SUMMARY OF THE INVENTION
Applicants have realized that, if the robot works systematically
within the area to be covered, there is no need to create the
map.
It is therefore an object of the present invention to provide an
autonomous robot, for performing area coverage, which does not
create a map of the area to be covered.
There is therefore provided, in accordance with a preferred
embodiment of the present invention, a robotic system for
systematically moving about an area to be covered. The system
includes at least one boundary marker located along the outer edge
of the area to be covered, a robot with a navigation system and a
sensor unit. The navigation system navigates the robot in generally
straight, parallel lines from an initial location and turns the
robot when the robot encounters one of the boundary markers,
thereby to systematically move about the area to be covered. The
sensor unit senses proximity to one of the at least one boundary
marker.
Additionally, in accordance with a preferred embodiment of the
present invention, the sensor unit includes a unit for indicating
proximity to an obstacle within the area to be covered and the
navigation system includes a unit for turning the robot when the
unit for indicating indicates proximity to an obstacle.
Moreover, in accordance with a preferred embodiment of the present
invention, the unit for indicating is either a contact sensor or a
proximity sensor.
Further, in accordance with a preferred embodiment of the present
invention, the navigation system includes a unit for counting the
number of laps need to cover the area between an obstacle and a
boundary marker.
Still further, in accordance with a preferred embodiment of the
present invention, the system includes at least one obstacle marker
located along the outer edge of the obstacle.
Moreover, in accordance with a preferred embodiment of the present
invention, the at least one boundary marker is an electrified wire
receiving a first signal and the at least one obstacle marker is an
electrified wire receiving a second signal.
Alternatively, in accordance with a preferred embodiment of the
present invention, the at least one boundary marker is a post
having a first bar code and the at least one obstacle marker is a
post having a second bar code.
There is also provided, in accordance with a preferred embodiment
of the present invention, a robotic system for systematically
moving about an area to be covered. The system includes at least
one boundary marker located along the outer edge of the area to be
covered, at least one obstacle marker located along the outer edge
of an obstacle within the area to be covered, a robot for moving
about the area to be covered and a sensor unit for sensing
proximity to the boundary and obstacle markers and for
differentiating between the boundary and obstacle markers.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be understood and appreciated more fully
from the following detailed description taken in conjunction with
the appended drawings in which:
FIG. 1A is a schematic illustration of an area to be covered and
the initial movement of a prior art robot within the area;
FIG. 1B is a block diagram illustration of the prior art robot;
FIG. 2A is a schematic illustration of an area to be covered and
the movement of a robot of the present invention within the
area;
FIG. 2B is a block diagram illustration of a robot, constructed and
operative in accordance with a preferred embodiment of the present
invention;
FIG. 3A is a schematic illustration of one embodiment of boundary
and obstacle markers;
FIG. 3B is a timing diagram operative for the embodiment of FIG.
3A;
FIG. 3C is a graphical illustration of the signal strength of a
magnetic sensor as a function of distance from the markers of FIG.
3A; and
FIG. 4 is a schematic illustration of an alternative embodiment of
boundary and obstacle markers.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
Reference is now made to FIGS. 2A and 2B which illustrate the
movement of a robot 40 of the present invention and the elements of
the robot, respectively. Similar reference numerals refer to
similar elements.
In accordance with a preferred embodiment of the present invention,
robot 40 does not create a map of the area to be covered. Instead,
it systematically scans within the area, moving in a straight
direction from one boundary marker to the next. To do so, it must
initially be placed relatively close to one extreme edge of the
boundary, for example at starting point 42, and faced in the
desired direction of scanning.
As can be seen in FIG. 2B, the robot 40 utilizes the odometer 24
and compass 26 but comprises a navigation system 41 and a sensor
system 43, shown as two sensors 44 and 46, for separately sensing
the boundary and the obstacles, respectively. Accordingly, there
can be two different types of markers, boundary markers 48 and
obstacle markers 50. The boundary markers 48 and obstacle markers
50 can be of any suitable types, as detailed hereinbelow.
Alternatively, for obstacles which stick above the ground, such as
trees and furniture, the obstacle sensors can be proximity and/or
contact sensors. For this system, there is no need for obstacle
markers and only boundary markers are utilized.
It will be appreciated that without a map, robot 40 does not know
its position within the area to be scanned; it only knows its
absolute position. Using position information, robot 40 scan the
area, moving in a generally straight line from one marker to the
next, as determined by sensor system 43. Using the output of
compass 26, the navigation system 41 then turns robot 40 generally
180.degree. whenever it encounters a new marker. The navigation
system 41 also ensures that the new "lap" is beside, and possibly
slightly overlapping, the previous lap, thereby to ensure full
coverage of the area to be covered. This is described in detail in
U.S. patent application Ser. No. 08/554,691.
In general, robot 40 moves in generally straight, parallel lines
between two boundary markers 48, as indicated by arrows 52.
However, if sensor system 43 indicates that the robot 40 is close
to an obstacle marker 50, the navigation system 41 causes the scan
to occur between boundary markers 48 and obstacle markers 50, as
indicated by arrows 54, counting the number of laps until the
obstacle is passed. The next lap, arrow 38, brings the robot 40 to
a boundary marker 48 on the other side of the obstacle 14. The
robot 40 then performs a scan in the opposite direction, between
the boundary markers 48 and the obstacle markers 50, to cover the
area behind the obstacle 14. This scan is shown with arrows 56 and
involves the same number of laps as for the first side of the
obstacle 14.
Once the scan behind the obstacle 14 is finished, the robot 40
follows the boundary markers 48 until it reaches the point, labeled
60, where it began the scan behind the obstacle 14, at which point,
it continues normal scanning between boundary markers 48.
Alternatively, the scan behind the obstacle 14 can be performed
without counting laps. Instead, the scan continues until the
obstacle 14 has been passed. This requires noting the location of
the robot 10 near the boundary when the robot 10 begins the scan
behind the obstacle 14 so that the robot 10 can be returned to that
location once the scan behind the obstacle 14 is finished.
It will be appreciated that, by scanning systematically between
boundary and obstacle markers, the present invention covers the
area to be covered without having to produce a map of the area.
Reference is now made to FIGS. 3A, 3B and 3C which respectively
illustrate one set of boundary and obstacle markers formed of
wires, a timing diagram for the markers and a graph of signal
strength as a function of distance from the wire.
In this embodiment, both the boundary marker 48 and the multiple
obstacle markers 50 are formed of wires connected to a power supply
60 via a wave generator 62. The wave generator 62 provides one type
of signal for the boundary marker 48 and another type of signal to
all of the obstacle markers 50.
For example, the signal for marker 48 might be of one frequency
while the signal for markers 50 might be of a second frequency. In
this embodiment, the wave generator 62 includes two separate
elements, each of which produces one of the two frequencies and
provides it to the appropriate set of wires.
Alternatively and as shown in FIG. 3B, the signals can be time
shared. In this embodiment, a short synchronization pulse 64 is
followed by a boundary signal 66 for marker 48 after which an
obstacle signal 68 for markers 50 is provided. The sequence
repeats. The marker is determined to be a boundary marker or an
obstacle marker by the length of time from the most recent
synchronization pulse 64.
It will be appreciated that, for both embodiments, the robot,
labeled 70, has a single magnetic sensor 72 for sensing the signals
from wave generator 62 and a processor 74 for determining if the
type of signal based on the frequency of the transmission, in the
first embodiment, or based on the timing of the transmission, in
the second embodiment. Alternatively, for the second embodiment,
the robot 70 can have separate receivers, each tuned to the
relevant frequency, and separate processors for each receiver to
determine if the received signal is strong enough to indicate
proximity.
FIG. 3C schematically illustrates the strength of the signal as a
function of distance from the location of the wire. When the sensor
72 is on top of the wire, no signal is received (point 80). As the
sensor 72 moves away from the wire, the signal increases sharply,
reaching a peak 82 within 50 cm. The signal then slowly decays as
the sensor 72 moves further away from the wire. Thus, as the robot
70 approaches the wire, the signal will slowly increase in
strength. Acceptable proximity can be defined as once peak 82 has
been reached or any time after peak 82 has been reached.
Reference is now made to FIG. 4 which illustrates an alternative
embodiment of the boundary and obstacle markers 48 and 50,
respectively. In this embodiment, the markers are formed of posts,
each having a different bar code written thereon. FIG. 4 uses
squares to indicate the boundary markers 48 and circles to indicate
obstacle markers 50. In this embodiment, as in the previous
embodiment there is a single sensor. In this case, the sensor is a
bar code reader which provides one type of signal when it reads the
boundary marker code and another type of signal when it reads the
obstacle marker code.
Alternatively, the boundary markers 40 can be formed of a wire and
the obstacle markers can be formed of bar coded posts, or vice
versa. A further alternative, discussed hereinabove, uses markers
only for the boundary and contact or proximity sensors for sensing
the proximity of an obstacle.
It will be appreciated that the markers can be formed of any
suitable marking unit and that the robot includes a sensor or
sensors capable of recognizing the information which the marking
unit provides to determine proximity. Such sensors and marking
units are discussed in detail in U.S. patent application Ser. No.
08/554,691. The number of sensors used is of little importance to
the present invention; however, the information from the types of
sensors must be separatable.
It will be appreciated by persons skilled in the art that the
present invention is not limited by what has been particularly
shown and described herein above. Rather the scope of the invention
is defined by the claims that follow.
* * * * *